It has been requested that electronic components used in boards with built-in electronic components be thinned while maintaining high performance, and this has been studied from various angles (for example, Japanese Unexamined Patent Publication Nos. 2008-34417 and 2008-34418). So far, electronic components have been manufactured in shapes corresponding to the boards when the boards with built-in electronic components have been manufactured in consideration of handleability, positioning accuracy, or the like. After electronic components are mounted on the hoards, the electronic components are processed into desired shapes by patterning or like.